const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const chalk = require('react-dev-utils/chalk');
const paths = require('./paths');

// Ensure the certificate and key provided are valid and if not
// throw an easy to debug error
function validateKeyAndCerts({ cert, key, keyFile, crtFile }) {
    let encrypted;
    try {
        // publicEncrypt will throw an error with an invalid cert
        encrypted = crypto.publicEncrypt(cert, Buffer.from('test'));
    } catch (err) {
        throw new Error(`The certificate "${chalk.yellow(crtFile)}" is invalid.\n${err.message}`);
    }

    try {
        // privateDecrypt will throw an error with an invalid key
        crypto.privateDecrypt(key, encrypted);
    } catch (err) {
        throw new Error(`The certificate key "${chalk.yellow(keyFile)}" is invalid.\n${err.message}`);
    }
}

// Read file and throw an error if it doesn't exist
function readEnvFile(file, type) {
    if (!fs.existsSync(file)) {
        throw new Error(
            `You specified ${chalk.cyan(type)} in your env, but the file "${chalk.yellow(file)}" can't be found.`
        );
    }
    return fs.readFileSync(file);
}

// Get the https config
// Return cert files if provided in env, otherwise just true or false
function getHttpsConfig() {
    const { SSL_CRT_FILE, SSL_KEY_FILE, HTTPS } = process.env;
    const isHttps = HTTPS === 'true';

    if (isHttps && SSL_CRT_FILE && SSL_KEY_FILE) {
        const crtFile = path.resolve(paths.appPath, SSL_CRT_FILE);
        const keyFile = path.resolve(paths.appPath, SSL_KEY_FILE);
        const config = {
            cert: readEnvFile(crtFile, 'SSL_CRT_FILE'),
            key: readEnvFile(keyFile, 'SSL_KEY_FILE'),
        };

        validateKeyAndCerts({ ...config, keyFile, crtFile });
        return config;
    }
    return isHttps;
}

module.exports = getHttpsConfig;
